The combination of four biomarkers measured using an immunoassay (REG3A, MMP2, HAMP and PRDX6) with the clinical variables of age and sex had a AUC of 0.69 (0.5–0.93) to predict AKI-SP2 compared to AKI-SP1 and no AKI. Here, MMP2 is linked to acute kidney injury.